A proportion of electricity charges to an operational cost of a data center is large. According to a certain survey, the proportion of electricity charges to the operational cost of the data center is approximately 32.4%, although a proportion of electricity charges to a production cost of a large manufacturer is approximately 3%. Therefore, a company that manages the data center makes various efforts to reduce electricity consumption in the data center.
For example, a certain document focuses on a fact that resources of a physical server in the data center are not effectively used and electricity consumption becomes high as a result. Specifically, it is proposed to reallocate, based on a usage rate of the resources of the physical server, the resources to be allocated to virtual machines in order to reduce resources which are not used and reduce electricity consumption in a whole system.
Patent Document 1: Japanese Laid-open Patent Publication No. 2010-61278
However, even though the technique described above is used, there's a case where the resources of the physical server are not effectively used and a reduction of electricity consumption is not enough.